Heat and pressure consolidated laminates are generally produced utilizing a core material comprising a plurality of phenolic resin impregnated paper sheets, a decor sheet impregnated with a melamine-formaldehyde resin and, optionally, a melamine-formaldehyde resin impregnated overlay sheet. These laminates have found world-wide success as construction materials, that is, wall panels, counter tops, and so forth, in the home and office. They can be prepared so as to function in a variety of service applications and can be produced with surfaces of high gloss, a matte finish or an embossed finish. They can be rendered post-formable with the application of heat and can be cut or worked much in the same manner as other building materials.
Although the above-described laminates have found a high degree of success over the past forty years, there is a continual need to improve the laminates and/or the method of preparation and, accordingly, research is always on the lookout for means to achieve such improvements.
One of the properties of heat and pressure consolidated laminates for which an ongoing search for improvement is continually being conducted is the elimination of the dark edge line present in all laminates containing cores produced from phenolic resins.
The dark edge line that is perceptible when conventional laminates are cut or worked has been a particularly difficult problem. If the resin impregnated into the core sheets is a phenolic resin a photo-darkening takes place upon exposure to light, resulting in the undesirable edge line. Even if a water-white phenolic resin is employed as the core resin, a photo-darkening of the exposed edge will take place with time. If a water-clear, melamine/formaldehyde resin which is not modified in accordance with the present invention, is used to replace the phenolic resin, laminates made therefrom do not meet the required NEMA standard properties for high pressure decorative laminate.
Accordingly, a long felt need would be satisfied if the dark edge line of decorative laminates could be improved, i.e. could be matched with the color of the decor sheet or be of a color of the designer's choice.